Pressure ulcer prosthesis and method for treating and/or preventing pressure ulcers

ABSTRACT

A pressure ulcer prosthesis ( 10 ) having an elongated body ( 11 ) to support a patient&#39;s limb. The body ( 11 ) has a longitudinally extending support surface ( 13 ) that is arcuate and concave in transverse cross section. A distal end ( 12 ) having a surface ( 18 ) extends away from the surface ( 13 ) so as to diverge therefrom so that a portion of the limb adjacently surface ( 18 ) is released from pressure.

TECHNICAL FIELD

The present invention relates to a prosthesis for treating and/orpreventing pressure ulcers. The invention also relates to a method oftreating and/or preventing pressure ulcers. More particularly thepresent invention is directed to a prosthesis and method for treatingand/or preventing pressure ulcers on the foot of the patient, and moreparticularly still, on or around the lateral malleolus and calcaneus ofthe patient's foot.

BACKGROUND OF THE INVENTION

Immobility, prolonged periods of lying down such as following surgery,peripheral vascular disease and diabetes are all examples of the kindsof things that are associated with pressure sores or pressure ulcers inpatients.

Patients who are lying down for prolonged periods are particularly proneto developing pressure ulcers on or around the calcaneus and lateralmalleolus of the foot. Patients with diabetes are highly susceptible todeveloping diabetic foot ulcers caused by poor circulation and patientswith peripheral vascular disease are susceptible to developing arterialulcers.

In such patients, mechanical pressure, moisture, friction and shearingforces all predispose to the development of pressure ulcers (see forexample, Harrison's Principles of Internal Medicine, 14^(th) edition,Fauci et al (eds), 1998, McGraw Hill, at 43).

There are a wide variety of prosthesis which have been developed fortreating and/or preventing pressure ulcers. However, many of these, suchas U.S. Pat. No. 4,197,845, U.S. Pat. No. 5,449,339, U.S. Pat. No.4,186,738 and U.S. Pat. No. 4,104,746 all make some contact with thesole of the patient's foot making it potentially difficult for thepatient to walk whilst wearing the prosthesis.

In addition, each of the above mentioned prior art examples, as wellU.S. Pat. No. 5,957,874, all have the effect, that when the patient iswearing them and is supine, the height of the patient's foot relative tothat of their knee is greater, causing the patient's leg to hyperextend.This can be uncomfortable and is not overcome by the prior art mentionedabove. with the prosthesis body. In others, the reinforcement structureis connected to or secured by a securing means to the prosthesis body.

In yet still further preferred embodiments, the reinforcement structureextends around a perimeter of the outer surface of the prosthesis bodyjust inwardly from an edge of the perimeter.

In such embodiments, the reinforcement structure has a width and forms aframe-like structure on the outer surface of the prosthesis body Inalternative embodiments the reinforcement structure is essentiallyblock-like and covers almost the entire outer surface of the prosthesisbody. In further alternative embodiments, the reinforcement structure isa strip running along a longitudinal axis of the outer surface of theprosthesis body. In yet still further alternative embodiments, thereinforcement structure is a strip running along a horizontal axis ofthe outer surface of the prosthesis body.

In further alternative embodiments there are a plurality ofreinforcement structures on the outer surface of the prosthesis bodyrunning along either the longitudinal or horizontal axis, or somerunning along one axis while others running along the opposite axis.

In yet still further alternative embodiments, the reinforcementstructures may form a cross-hatched pattern on the outer surface of theprosthesis body, or any other pattern capable of further reinforcing therigidity of the prosthesis body.

In yet still further preferred embodiments the prosthesis furthercomprises at least one fitting strap for securing the prosthesis to thepatient's limb. The fitting strap can be formed of velcro, or any othermaterial suitable for maintaining the prosthesis in the appropriateposition.

In further preferred embodiments there are two fitting straps eachlocated proximal a respective end of the prosthesis. In alternativeembodiments there are a plurality of fitting straps on the prosthesisThe prosthesis of preferred embodiments further comprises at least oneanti-hyperextension means on the outer surface of the prosthesis' bodyproximal a proximal end of the prosthesis.

The preferred anti-hyperextension means prevents the patient's limb fromhyper-extending when the prosthesis is being worn by the patient whilethe patient is supine on a surface, such as a bed. Hyperextension iscaused when the patient's leg comes under a further extension pressureabove and beyond that which the patient feels when the patient's leg isnaturally fully extended,

Preferred anti-hyperextension means have a rectangular prism-type shapebut follow a contour of the outer surface of the prosthesis body.Alternative embodiments of the anti-hyperextension means are of anyshape provided that the shape allows the anti-hyperextension means toadequately perform its preferred function as described above.

In all such embodiments the anti-hyperextension means may be integralwith, connected to, or secured to the prosthesis body. Theanti-hyperextension means of the present invention can be formed of anymaterial provided that the material allows the anti-hyperextension meansto perform its preferred function as described above.

In a second aspect, the present invention provides a method of treatingand/or preventing pressure ulcers on a patient's foot, said methodcomprising placing a prosthesis of the first aspect on the patient'sleg, such that when the patient is supine on a substantially horizontalsurface, the prosthesis prevents the calcaneus and lateral malleolus ofthe patient's foot from contacting the substantially horizontal surfaceor the prosthesis.

In a third aspect, the present invention provides a prosthesis of thefirst aspect when used for the treatment and/or prevention of pressureulcers on a patient's foot.

In preferred embodiments of the method of the second aspect, theprosthesis is placed on the posterior of the patient's lower leg belowthe popliteal fossa. Preferably, once the prosthesis is so placed, thelower leg is supported such that the patient's foot is suspended whenthe patient is supine on a substantially horizontal surface. Thesuspension is such that the patient's lateral malleolus and calcaneusare prevented from coming into contact with the substantially horizontalsurface on which the patient is supine, or the prosthesis.

Note that when the patient is supine on a substantially horizontalsurface, there is the possibility that because an edge of the distal endof the prosthesis body may elevate the distal end of the patient's leg,the patient's leg will be caused to hyperextend.

As explained earlier, the preferred prosthesis further comprises ananti-hyperextension means. When such prosthesis has been placed on thepatient's leg as described above, and the patient is supine on asubstantially horizontal surface, the anti-hyperextension meanspreferably rests on the substantially horizontal surface. As aconsequence, the anti-hyperextension means preferably ensures that thepatient's knee is at the same relative height as his/her foot, or isrelatively higher than his/her foot, with respect to the substantiallyhorizontal surface. In that way the anti-hyperextension means preferablyprevents the patient's leg from hyperextending.

Also as explained earlier, a preferred prosthesis further comprises atleast one fitting strap for securing the prosthesis to the patient'sleg. There are at least two advantages associated with securing theprosthesis to the patient's leg. First, the prosthesis is unlikely to bedislodged from its appropriate position if the patient moves. Second,the patient is free to ambulate without having to remove the prosthesis.Indeed, when the prosthesis is placed on the patient's leg as discussedabove, no part of the prosthesis would interfere with the patient'sability to walk whilst wearing it.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred form of the present invention will now be described by wayof example with reference to the accompanying drawings wherein:

FIG. 1 is a rear perspective view of a preferred embodiment of thepressure ulcer prosthesis of the present invention.

FIG. 2 is a front perspective view of a preferred embodiment of thepressure ulcer prosthesis of the present invention. FIG. 3 is aschematic diagram illustrating a preferred embodiment of the pressureulcer prosthesis of the present invention being worn by a patient in theappropriate position,

FIG. 4 is a schematic diagram of the lower leg of the patient.

FIG. 5 is a schematic diagram illustrating a patient lying on a bedwearing a 20 pressure ulcer prosthesis of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The pressure ulcer prosthesis 10 of the preferred embodiment of thepresent invention comprises an elongate body 11 to support a patient'slimb, said body 11 having: a longitudinal axis 90 and a longitudinallyextending support surface 13 for the limb, said support surface 13 intransverse cross-section being arcuate and concave; and a distal end 12with a further surface 80 extending from the support surface 13 so as todiverge from the longitudinal axis 90 such that a portion of the limbadjacent the further surface 80 is relieved from pressure.

In preferred embodiments, the body 11 in transverse cross-section isarcuate and concave.

The preferred prosthesis 10 further comprises a liner 20 for lining thesupport surface 13 of the prosthesis body 11. The liner 20 is preferablyformed from a high density foam. Preferably, the liner 20 hassubstantially the same shape as the support surface 13 of the prosthesisbody 11. Of course, where appropriate, a liner surface 21 which remainsin contact with the patient's body may have the same contour of thepatient's body on which it will be worn.

The preferred prosthesis 10 further comprises at least one reinforcementstructure 30 on an outer surface 14 of the prosthesis body 11 forreinforcing the prosthesis's rigidity. As shown in FIG. 1, thereinforcement structure 30 of preferred embodiments extends around aperimeter of the outer surface 14 of the prosthesis body 11 justinwardly from an edge of the perimeter.

In such embodiments, the reinforcement structure 30 has a width andforms a frame-like structure on the outer surface 14 of the prosthesisbody 11.

As is illustrated in FIGS. 1-3 and 5, the preferred prosthesis 10further comprises two fitting straps 40 for securing the prosthesis 10to the patient's body. The preferred fitting straps 40 are formed ofvelcro. Typically, the fitting straps 40 are each located proximal arespective end of the prosthesis 10.

The prosthesis 10 of preferred embodiments further comprises at leastone anti-hyperextension means 50 on the outer surface 14 of theprosthesis body 11 proximal a proximal end of the prosthesis 10.

As shown in FIG. 1, preferred anti-hyperextension means 50 has arectangular prism-type shape but follows a contour of the outer surface14 of the prosthesis body 11.

As discussed above, the preferred anti-hyperextension means 50preferably prevents the patient's limb from hyperextending when theprosthesis 10 is being worn by the patient while the patient is supineon a substantially horizontal surface 70, such as a bed. This particularfunction of the anti-hyperextension means 50 is discussed in more detailbelow.

Preferred embodiments of the present invention also provide a method oftreating and/or preventing pressure ulcers on a patient's foot 60. Thepreferred method comprises placing a prosthesis 10 on the posterior 63of the patient's lower leg 68 below the popliteal fossa 64.

Once the prosthesis 10 is so placed, the lower leg 68 is preferablysupported such that the patient's foot 60 is suspended when the patientis supine on a substantially horizontal surface 70, as shown in FIGS. 3and 5. The suspension is such that the patient's lateral malleolus 62and calcaneus 61 are prevented from coming into contact with thesubstantially horizontal surface 70 on which the patient is supine, orthe prosthesis 10.

As can be seen in FIGS. 3 and 5, when the patient is supine on asubstantially horizontal surface 70, there is the possibility thatbecause an edge of the distal end 12 of the prosthesis body 11effectively elevates the distal end of the patient's lower leg 68, thepatient's leg will be caused to hyperextend. As discussed earlier,hyperextension is caused when the patient's leg comes under a furtherextension pressure above and beyond that which the patient feels whenthe patient's leg is naturally fully extended.

Accordingly, preferred embodiments of the invention disclose that whenthe prosthesis 10 is properly placed on the patient's lower leg 68, theanti-hyperextension means 50 rests on the substantially horizontalsurface 70 in such a way as to ensure that the patient's knee 65 is atthe same relative height as the patient's foot 60, or is relativelyhigher than the patient's foot 60, with respect to the substantiallyhorizontal surface 70. In that way, the anti-hyperextension means 50preferably prevents the patient's leg from hyperextending.

As explained earlier, the fitting straps 40 secure the prosthesis 10 tothe patient's leg. Having such straps provides the advantage that theprosthesis 10 is unlikely to be dislodged from its appropriate positionif the patient moves around whilst lying on a substantially horizontalsurface 70, such as a bed. The further advantage is that when theprosthesis I 0 is placed on the patient's leg as discussed above, nopart of the prosthesis 10 would interfere with the patient's ability towalk whilst wearing it.

1. A pressure ulcer prosthesis comprising an elongate body to support apatient's limb, said body having: a longitudinal axis and alongitudinally extending support surface adapted to receive an undersideof a limb, said support surface in transverse cross-section beingarcuate and concave; and a distal end with a further surface extendingfrom the support surface so as to diverge from the longitudinal axissuch that a portion of the limb adjacent the further surface is relievedfrom pressure.
 2. The prosthesis of claim 1, wherein, the prosthesisbody has a lower surface that in transverse cross-section is arcuate andconcave.
 3. The prosthesis of claim 1, wherein, the prosthesis body is ashape suitable for accommodating the support surface for the limb andsimultaneously providing an appropriate shape capable of enabling apatient wearing the prosthesis to comfortably lie supine on asubstantially horizontal surface.
 4. The prosthesis of claim 1, wherein,the prosthesis body has at least one hole for providing ventilation toan area of the limb on which the prosthesis is placed.
 5. The prosthesisof claim 4, wherein, there is a plurality of holes through theprosthesis body.
 6. The prosthesis of claim 1, wherein, the prosthesisfurther comprises a liner for lining the support surface.
 7. Theprosthesis of claim 6, wherein, the liner is formed from a high densityfoam.
 8. The prosthesis of claim 6, wherein, the liner is formed from alow density foam.
 9. The prosthesis of claims 6,wherein, the liner issubstantially the same shape as the support surface of the prosthesisbody.
 10. The prosthesis of claim 1, wherein, the prosthesis furthercomprises at least one reinforcement structure on an outer surface ofthe prosthesis body for reinforcing the prosthesis' rigidity.
 11. Theprosthesis of claim 10, wherein; the reinforcement structure is integralwith the prosthesis body.
 12. The prosthesis of claim 10, wherein; thereinforcement structure extends around a perimeter of the outer surfaceof the prosthesis body just inwardly from an edge of the perimeter. 13.The prosthesis of claim 12, wherein, the reinforcement structure has awidth and forms a frame-like structure on an outer surface of theprosthesis body.
 14. The prosthesis of claim 10, wherein, thereinforcement structure is essentially block-like and covers almost theentire outer surface of the prosthesis body.
 15. The prosthesis of claim10, wherein, the reinforcement structure is a strip running along alongitudinal axis of the outer surface of the prosthesis body.
 16. Theprosthesis of claim 10, wherein, the reinforcement structure is a striprunning along a horizontal axis of an the outer surface of theprosthesis body.
 17. The prosthesis of claim 1, further including aplurality of reinforcement structures on the outer surface of theprosthesis body running along either longitudinally or transverse of theprosthesis.
 18. The prosthesis of claim 10, wherein, the reinforcementstructures may form a cross-hatched pattern on the outer surface of theprosthesis body, or any other pattern capable of further reinforcing therigidity of the prosthesis body.
 19. The prosthesis of claim 1, furthercomprises at least one fitting strap for securing the prosthesis to thepatient's limb.
 20. The prosthesis of claim 19, wherein, there are twofitting straps each located proximal a respective end of the prosthesis.21. The prosthesis of claim 1, further comprises at least oneanti-hyperextension means on the outer surface of the prosthesis' bodyproximal a proximal end of the prosthesis.
 22. The prosthesis of claim21, wherein, the anti-hyperextension means have a rectangular prism-typeshape and follows a contour of the outer surface of the prosthesis body.23. The prosthesis of claim 1, including a sleeve within which said bodyis located.
 24. The prosthesis of claim 23, wherein said sleeve includesa pair of sheet members secured together and enclosing a pocket withinwhich the body is located.
 25. The prosthesis of claim 23, wherein saidsleeve is provided with padded areas to engage a patient's ankles. 26.The prosthesis of claim 23 wherein said has a cavity to receive aninsert.
 27. The prosthesis of claim 1 wherein the prosthesis issymmetrical about a central longitudinal plane, and is adapted to wornon either a left or right limb.
 28. The prosthesis of claim 10, whereinthe reinforcement structure is connected, or secured by securing means,to the prosthesis body.
 29. A prosthesis for treating or preventingpressure ulcers in a lower leg of a patient, the prosthesis comprising:(a) body means, comprising an elongate body, for supporting the lowerleg such that, when the patient is supine on a substantially horizontalsurface, (a) a foot of the lower leg is suspended with a lateralmalleolus and calcaneus of the foot prevented from coming into contactwith the substantially horizontal surface or the body means, and (b) thefoot is suspended above the substantially horizontal surface at a heightthat is the same as or lower than a height at which a knee of the lowerleg is disposed above the substantially horizontal surface, the elongatebody having a longitudinal axis and a longitudinally extending supportsurface, said support surface in traverse cross-section being arcuateand concave, said elongate body having a distal end with a furthersurface extending from the support surface so as to diverge from thelongitudinal axis, and (b) means for securing the elongate body to thelower leg.
 30. A method for treating or preventing pressure ulcers in alower leg of a patient, comprising (a) providing the pressure ulcerprosthesis of claim 1, and (b) securing the elongate body to theunderside of the lower leg below the popliteal fossa such that, when thepatient is supine on a substantially horizontal surface, the foot of thelower leg is suspended with a lateral malleolus and calcaneus of thefoot prevented from coming into contact with the substantiallyhorizontal surface or the elongate body.